The pleasure proper to a good activity is good, while the pleasure proper to a bad activity is evil. A pleasure which is proper to an activity makes the activity more accurate, more enduring, and better, while an alien pleasure impairs the activity. Pleasure resides in the activity which is perfected by that pleasure. There can be no pleasure without activity, and pleasure perfects every activity. Why is it impossible to be continuously pleased? Human activities cannot be continued indefinitely, and therefore neither can pleasure. Activities are most pleasant when the faculty is at its best and is directed toward its best corresponding object. Pleasure makes the activity perfect, but not in the same way as a sensible object or sensation. The most pleasant activity is the most perfect. There is pleasure with respect to every faculty of sensation, as well as with thought and contemplation. The best activity of each faculty of sensation is that which is the best disposed toward the best object with which that faculty is concerned. Yet pleasure is complete at every point during the time in which one is pleased. What is pleasure? It is not a motion, for motion require an interval of time for their completion. Further, not all pleasures are worthy of choice, but only those which come from noble actions. Yet pleasure is not the highest good, because it is preferable with rather than without prudence, as Plato argues. An object which is choiceworthy in the greatest sense is chosen for its own sake, and pleasure seems to be such an object. Observation shows that both rational and nonrational animals aim at pleasure. For some say it is the ultimate good while others claim it is entirely bad. There is however, a great disagreement among philosophers with regard to pleasure. Further, the formation of a virtuous character perhaps depends primarily on being formed so as to enjoy what one should and hate what one should. For this reason the education of the young is guided by means of pleasures and pains. Pleasure is thought to be one of the things most closely associated with human life.

Aristotle nichomachean